1. Field of the Invention
The present invention relates generally to the treatment of arterial disease, including for example, aortic occlusive disease, and in particular, to an improved stent assembly and method for treating arterial disease at the intersection of a plurality of arteries or blood flow passageways such as the intersection of the aorta and renal arteries or the aorta and posterior spinal arteries.
2. Prior Art
The prior art describes treatment of arterial disease by various surgical techniques, some involving the use of stents and grafts. For example, it is well known in the art to interpose within the diseased portion of an artery a stent, whether made of stainless steel, nitinol or other materials capable of being balloon-expanded, for strengthening the walls of a stenotic or occluded artery. Grafts, comprised of hollow tubes of material such as dacron, are normally inserted within the walls of a damaged artery and can be sewn into position or expanded through the use of a stented balloon catheter. It is also well known in the prior art to use a graft in conjunction with a stent to repair highly damaged portions of the aorta or other arteries thereby ensuring blood flow and reducing the risk of an aneurysm or rupture.
A more severe problem occurs when it is desirable to use a graft or a stented graft at or around the intersection of a major artery (e.g., the aorta) with intersecting collateral arteries (e.g., the renal arteries). While a stented graft is clearly preferred to strengthen and ensure the flow of blood through the aorta, the use of a stented graft effectively seals or blocks off the blood flow to collateral organs, such as the kidneys. One such technique for repairing weakened arterial walls is described in U.S. Pat. No. 5,617,878 to Taheri (Stent and Method for Treatment of Aortic Occlusive Disease). The method includes placing a graft at the intersection of two arteries. A device is used to make an opening in the graft at a point corresponding to the intersection of the two arteries. A stent is inserted into the graft and through the graft opening; the stent having a cylindrical collar with tines which grab and catch the walls of the graft to attach the stent to the opening in the graft whereby the flow of blood at the intersection of the arteries is ensured. The use of a "bifurcated" stent comprised of a single stent and graft adapted through cutting to incorporate a second stent and graft is described in U.S. Pat. No. 5,755,772 to Evans et al. The prior art techniques, while effective, have proven cumbersome and somewhat difficult to employ and execute.
The present invention solves the problems of the prior art by providing a novel and improved stent assembly and method for treating arterial disease through the use of first and second stents or first and second stented grafts mated to each other at the intersection of an occluded or diseased main artery and a collateral artery by a unique locking structure.